A number of studies (Harford et al., 2005; Kahler and Strong, 2006) indicate variation in symptom prevalence due to wording and interpretation. Studies have noted difficulties in the assessment of tolerance in population surveys, particularly in younger populations (Chung et al., 2001; Martin et al., 2006). Chung and colleagues (2001) have argued that the assessment of tolerance among adolescents and younger adults reflects low to moderate levels of tolerance rather than a pathological process indicative of alcohol dependence. Harford and colleagues (2005) further note that the endorsement of the criterion much time spent obtaining alcohol, drinking, or getting over its effects in adolescents is more reflective of time spent rather than of getting over its effects (5.2 percent versus 0.4 percent among males and 5.2 percent versus 0.8 percent among females) and, therefore, may reflect problems in obtaining alcohol rather than indicating a clinically relevant aspect of alcohol dependence. A further example is found for the criterion drink more/longer; one that yields high prevalence in most studies. In contrast, Harford and colleagues (2005) report lower prevalence for this criterion based
